P1171, assuming you have the NA engine on your '99 S80 (B6304S3), is fuel trim upper limit (ECM-261A)

ECM-261A

Diagnostic trouble code (DTC) information

Condition

The control module receives information from the heated oxygen sensor (HO2S) about the fuel / air mixture when idling at both the lower and upper part-load range. If the fuel / air mixture deviates from λ=1, the short-term fuel trim will compensate for this by adjusting the injection time so that λ=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) ECM-261A will be stored when the long-term trim must be adjusted to almost maximum in the lower part load area.


Substitute value
none


Possible source

Upper limit:
-intake air leakage
-exhaust system air leakage
-low fuel pressure
-defective heated oxygen sensor (HO2S)




To check:

Check for air leaks, intake and exhaust. Air can also leak in through the CP canister, the Brake booster, and the SAS valve, so check everything. Then check fuel pressure jump fuel pump relay and it should read 300kPa. Then check residual pressure (turn off pump and wait 20 mins) shouldn't be below 200kPa. Could be your MAF at this point, so pulling a junkyard one and trying it might give you an answer.

Note, after you find/fix any areas pull the battery off for 20+ minutes to reset fuel trim before you replace the MAF/O2 sensor. If you replace one, reset fuel trim again before you replace the other.

As to "rotor", I have no idea.
--
If you're not driving it "like its stolen," are you really driving?